More Companies Taking Advantage of Rule Allowing Them to Reincorporate Overseas to Lower Tax Bills

President Barack Obama threw himself into the politically charged effort to block U.S. firms from reincorporating overseas for tax reasons, calling the relocations "wrong" and urging Congress to stop them through quick-fix legislation.

Such corporate relocations, known as inversions, could become a wild card in Washington in the coming weeks, particularly if more big companies announce plans to move before the midterm elections in November.